package ly.jobdu;

import java.util.Scanner;

public class Q1092Fibonacci {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		while (scanner.hasNext()) {
			int a = scanner.nextInt();
			System.out.println(getFibonaci(a));
		}
	}

	public static int getFibonaci(int n) {
		if (n == 0) {
			return 0;
		} else if (n == 1) {
			return 1;
		} else {
			return getFibonaci(n - 1) + getFibonaci(n - 2);
		}
	}
}
